<head>
    <meta charset="utf-8" />
    <title>优先级效果</title>
    <style>
        #one {
            color: red;
        }

        .oneClass {
            color: green;
        }

        p {
            color: blue;
        }
    </style>

<body>
    <p id="one" class="oneClass">段落</p>
</body>

</html>